libata: replace tf_read with qc_fill_rtf for non-SFF drivers

Now that all SFF stuff is separated out of core layer, core layer
doesn't call ops->tf_read directly.  It gets called only via
ops->qc_fill_rtf() for non-SFF drivers.  This patch directly
implements private ops->qc_fill_rtf() for non-SFF controllers and kill
ops->tf_read().

This is much cleaner for non-SFF controllers as some of them have to
cache SFF register values in private data structure and report the
cached values via ops->tf_read().  Also, ops->tf_read() gets nasty for
controllers which don't have clear notion of TF registers when
operation is not in progress.

As this change makes default ops->qc_fill_rtf unnecessary, move
ata_sff_qc_fill_rtf() form ata_base_port_ops to ata_sff_port_ops where
it belongs.

Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 1389c64..ad5b6f3 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -243,9 +243,9 @@
 static int ahci_scr_write(struct ata_port *ap, unsigned int sc_reg, u32 val);
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
 static unsigned int ahci_qc_issue(struct ata_queued_cmd *qc);
+static bool ahci_qc_fill_rtf(struct ata_queued_cmd *qc);
 static int ahci_port_start(struct ata_port *ap);
 static void ahci_port_stop(struct ata_port *ap);
-static void ahci_tf_read(struct ata_port *ap, struct ata_taskfile *tf);
 static void ahci_qc_prep(struct ata_queued_cmd *qc);
 static u8 ahci_check_status(struct ata_port *ap);
 static void ahci_freeze(struct ata_port *ap);
@@ -295,10 +295,10 @@
 	.sff_check_status	= ahci_check_status,
 	.sff_check_altstatus	= ahci_check_status,
 
-	.sff_tf_read		= ahci_tf_read,
 	.qc_defer		= sata_pmp_qc_defer_cmd_switch,
 	.qc_prep		= ahci_qc_prep,
 	.qc_issue		= ahci_qc_issue,
+	.qc_fill_rtf		= ahci_qc_fill_rtf,
 
 	.freeze			= ahci_freeze,
 	.thaw			= ahci_thaw,
@@ -1473,14 +1473,6 @@
 	return readl(mmio + PORT_TFDATA) & 0xFF;
 }
 
-static void ahci_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
-{
-	struct ahci_port_priv *pp = ap->private_data;
-	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
-
-	ata_tf_from_fis(d2h_fis, tf);
-}
-
 static unsigned int ahci_fill_sg(struct ata_queued_cmd *qc, void *cmd_tbl)
 {
 	struct scatterlist *sg;
@@ -1779,6 +1771,15 @@
 	return 0;
 }
 
+static bool ahci_qc_fill_rtf(struct ata_queued_cmd *qc)
+{
+	struct ahci_port_priv *pp = qc->ap->private_data;
+	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
+
+	ata_tf_from_fis(d2h_fis, &qc->result_tf);
+	return true;
+}
+
 static void ahci_freeze(struct ata_port *ap)
 {
 	void __iomem *port_mmio = ahci_port_base(ap);